docs: def _process_omia_omim_map(self, row):
          """
          Links OMIA groups to OMIM equivalents.
          :param row:
          :return:
          """
          # omia_id, omim_id, added_by
          model = Model(self.graph)
          omia_id = 'OMIA:' + row['omia_id']
          omim_id = 'OMIM:' + row['omim_id']
  
          # also store this for use when we say that a given animal is
          # a model of a disease
          if omia_id not in self.omia_omim_map:
              self.omia_omim_map[omia_id] = set()
          self.omia_omim_map[omia_id].add(omim_id)
  
          if self.test_mode and omia_id not in self.test_ids['disease']:
              return
  
          model.addXref(omia_id, omim_id)
  
          return